Instant start lamp and circuit



J1me 1950 w. s. FROHOCK INSTANT-START LAMP AND CIRCUIT Filed July 30, 1948 IN VEN TOR.

ATTORNEY VVaPren S. Frohock Patented June 27, 1950 INSTANT START LAMP AND CIRCUIT Warren S. Frohock, Danvers, Masa,

Sylvania Electric Products Itr'ia,

asslgnor to Salem, Mass, a

corporation or Massachuset Application July 30, 1948, Serial No. 41,691

3 Claims.

This invention relates to electric gaseous discharge lamps, and particularly to long tubular lamps such as fluorescent or ultraviolet lamps.

Such lamps generally require high voltage for starting, this high voltage being provided by starting relays and switches, transformers or the like. The lamp of my invention, when connected in a proper circuit, will start at lower voltages without the need for starting relays or switches, and without the delay characteristic of such starting mechanisms. In fact, by replacing the starting relay in an ordinary fluorescent lamp fixture by a condenser, and using one of my novel fiuorescent lamps, instant starting may be achieved with no further circuit changes.

I achieve this result by using two separate electron-emissive electrodes at one end of the lamp, and connecting one of these electrodes back to the electrode at the other end of the lamp through a condenser. An electrode at the other end of the lamp will be sufilcient, although a. double electrode may be used if desired.

My lamp may be placed in the usual fluorescent lamp sockets in the same manner as an ordinary fluorescent lamp, it being unpolarized; that is either end may be placed into either socket. The usual starter can thus be removed and replaced by a condenser, and my lamp operated. The -annoyance and delay caused by such starters can thus be dispensed with. When the power is turned on, the lamp lights promptly, without the delay characteristic of such starters.

Other objects, features and advantages of the invention will be apparent from the following specification, tak ng with the accompanying drawings in which:

Figure 1 is a schematic diagram of a lamp and circuit according to the invention; and

Figure 2 is a drawing of the end of the lamp showing the double electrode.

In Figure 1 the lamp envelope l, which may be a long glass tube coated with fluorescent materials, for example, has at each end the bases 2, 3 from which the contact prongs 4, 5, 6, 7 extend and are insulated from each other in the usual manner, although prongs and 1 may be short-circuited to each other if desired. The electrode 9 may be the usual coiled-coil tungsten wire coated with one or more of the alkaline earth oxides, as shown for example, in U. S. Patent 2,250,158 to Erwin F. Lowry. Lead-in wires l1, l3 extend from the ends of electrode 9 through the end of envelope l and into the contact prongs 5 and 1. The electrodes '8, ID at the other end of the tube I are also the usual coiled-coil tungsten wire coated with one or more of the alkaline earth oxides, for example as shown in the same patent. These are arranged side by side as shown in more detail in Figure 2.

Lead-in wires l4, l5, l6, I! extend from the glass press l8 which extends into stem 19 which closes oi! the end of tube I. The wires are arranged in pairs, l4 and I5 being closer to each other than to It and H, to provide a, longer leakage path of insulation between the two electrodes assemblies, l0, l4, l5 and '8, l6, H. To confine the discharge to the coated coils 8 and Ill, the lead-in wires are coated with carbon, for example coated with a colloidal suspension of carbon in water (such as aquadag) and dried. Carbon is a conductor, but has a low electron-emissivity, and tends to prevent a discharge between the lead-in wires. confining the discharge to the coils 8, I0 helps to get them quickly to a proper electron-emitting temperature. The two coils 8 and III are arranged in the same plane and parallel to each other.

The base 2 may be of insulating material with the pins 4, B staked thereto by their split and flattened ends 20. The lead-in wires l4 and I5 may be twisted together outside the lamp stem Iii, that is between the stem l9 and the base 2 so that the lead-in wires l4, l5 are shorted in the finished lamp. During manufacture, the lead-in wires may be separated for passing current through the coil Ill, for activation in the usual manner in the art. Lead-in wires l6 and I! are also connected to each other in the finished lamp...

'Ihc'lamp may have a fluorescent coating 28, if desired, as shown in Figure 2. Th tube I will ordinarily have sealed therein a filling of one or more of the rare gases, for example, argon or krypton at a few millimeters pressure, and a drop of mercury to produce mercury vapor.

with the lead-in wires l4 and ,l5 from each end of electrode in connected to a single contact pin 6, and the lead-in wires from both ends of electrode 8 likewise connected to a single contact pin 4, and the lead-in wires ll, l3 from each end of coil 9 being each connected, respectively to a separate contact pin 5, 1, my lamp will be unpolarized or reversible, that is, either end of the lamp may be placed in either end of the usual sockets, that is, pins 4 and 6 may be connected to circuit wires 22, 23 in that order or its reverse, or to 24, 25 in that order or its reverse, as desired, the other contact pins 5, 1 being connected to the pair of circuit wires not connected to 4, 6. Thus to change a fixture from delayed-action starting 1 to my instant-starting, one need only change the usual starter interconnecting the ends of the lamp to a condenser 26 as shown, and then replace the present lamp by the lamp of m invention, without having to consider the question of which end of the lamp should be connected to which pair of wires.

If desired, of course, the pins 5, 1 may be shortcircuited to each other, but the pins 4, 6 should not be short-circuited to each other.

The coils 8 and 10 may be arranged parallel to each other and transverse to the longitudinal axis of the tube. I have found a separation oi! about 2 to 4 mm. between the coils to be effective, and a. typical coil may be of tungsten wire about 3 mils in diameter, formed into a coiled-coil with the coating material confined to the minor coil, that is the coil of smaller diameter, as shown, for example, in U. S. Patent 2,258,158 to Erwin F. Lowry.

The condenser 26, which may be of l mfd. capacity, is connected between electrode 8 and one end of electrode 9. The other end of electrode 9 may be connected to one end 28 of a line, of say 200 volts, for the usual 48-inch long, 1% inch diameter, 40 watt fluorescent lamp. The electrode Ill may be connected to the other end 21 of said line. An impedance 29, for example, an inductance is connected in one side of the line, for example side 28, as shown.

Although a condenser is shown as the impedance element 26, a resistance or inductance could be used. A condenser is preferable when the main impedance 29 is inductive, and vice-versa, to give a resonant voltage build-up, but a resistor can be used instead of condenser 26 if desired.

What I claim is:

1. An electric gaseous discharge lamp comprising: a long tubular envelope; a single, coiled filamentary electrode at one end thereof and coated with alkaline earth oxides; a pair of coiled filamentary electrodes, coated with alkaline earth oxides, at the other end thereof; lead-in wires from each end of each filament extending through the ends of said envelope; a base at each end of said envelope; two contacts extending from each base, the lead-in wires from each end of the single filament at one end of said envelope being' 2. The combination of claim 1, and a pair 01'- connections for each end of said lamp, an impedance joining one connection of one said pair to one connection of the other pair, the other connections of each pair extending to the terminals of a voltage source, and a ballast impedance in at least one of the latter two connections.

3. The combination of claim 1, and a pair of connections for each end of said lamp, 9. condenser joining one connection of one said pair to one connection of the other pair, the other connections of each pair extending to the terminals of a voltage source, and a ballast impedance in at least one of the latter two connections.

WARREN S. FROHOCK.

REFERENCES CITED The following references are of re ord in the file of this patent:

UNITED STATES PATENTS 

